<?php
/*
* This file is part of SwiftMailer.
* (c) 2004-2009 Chris Corbyn
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
/**
* DKIM Signer used to apply DKIM Signature to a message.
*
* @author Xavier De Cock <xdecock@gmail.com>
*/
class Swift_Signers_DKIMSigner implements Swift_Signers_HeaderSigner
{
/**
* PrivateKey.
*
* @var string
*/
protected $_privateKey;
/**
* DomainName.
*
* @var string
*/
protected $_domainName;
/**
* Selector.
*
* @var string
*/
protected $_selector;
/**
* Hash algorithm used.
*
* @see RFC6376 3.3: Signers MUST implement and SHOULD sign using rsa-sha256.
*
* @var string
*/
protected $_hashAlgorithm = 'rsa-sha256';
/**
* Body canon method.
*
* @var string
*/
protected $_bodyCanon = 'simple';
/**
* Header canon method.
*
* @var string
*/
protected $_headerCanon = 'simple';
/**
* Headers not being signed.
*
* @var array
*/
protected $_ignoredHeaders = array('return-path' => true);
/**
* Signer identity.
*
* @var string
*/
protected $_signerIdentity;
/**
* BodyLength.
*
* @var int
*/
protected $_bodyLen = 0;
/**
* Maximum signedLen.
*
* @var int
*/
protected $_maxLen = PHP_INT_MAX;
/**
* Embbed bodyLen in signature.
*
* @var bool
*/
protected $_showLen = false;
/**
* When the signature has been applied (true means time()), false means not embedded.
*
* @var mixed
*/
protected $_signatureTimestamp = true;
/**
* When will the signature expires false means not embedded, if sigTimestamp is auto
* Expiration is relative, otherwise it's absolute.
*
* @var int
*/
protected $_signatureExpiration = false;
/**
* Must we embed signed headers?
*
* @var bool
*/
protected $_debugHeaders = false;
// work variables
/**
* Headers used to generate hash.
*
* @var array
*/
protected $_signedHeaders = array();
/**
* If debugHeaders is set store debugData here.
*
* @var string
*/
private $_debugHeadersData = '';
/**
* Stores the bodyHash.
*
* @var string
*/
private $_bodyHash = '';
/**
* Stores the signature header.
*
* @var Swift_Mime_Headers_ParameterizedHeader
*/
protected $_dkimHeader;
private $_bodyHashHandler;
private $_headerHash;
private $_headerCanonData = '';
private $_bodyCanonEmptyCounter = 0;
private $_bodyCanonIgnoreStart = 2;
private $_bodyCanonSpace = false;
private $_bodyCanonLastChar = null;
private $_bodyCanonLine = '';
private $_bound = array();
/**
* Constructor.
*
* @param string $privateKey
* @param string $domainName
* @param string $selector
*/
public function __construct($privateKey, $domainName, $selector)
{
$this->_privateKey = $privateKey;
$this->_domainName = $domainName;
$this->_signerIdentity = '@'.$domainName;
$this->_selector = $selector;
// keep fallback hash algorithm sha1 if php version is lower than 5.4.8
if (PHP_VERSION_ID < 50408) {
$this->_hashAlgorithm = 'rsa-sha1';
}
}
/**
* Instanciate DKIMSigner.
*
* @param string $privateKey
* @param string $domainName
* @param string $selector
*
* @return self
*/
public static function newInstance($privateKey, $domainName, $selector)
{
return new static($privateKey, $domainName, $selector);
}
/**
* Reset the Signer.
*
* @see Swift_Signer::reset()
*/
public function reset()
{
$this->_headerHash = null;
$this->_signedHeaders = array();
$this->_bodyHash = null;
$this->_bodyHashHandler = null;
$this->_bodyCanonIgnoreStart = 2;
$this->_bodyCanonEmptyCounter = 0;
$this->_bodyCanonLastChar = null;
$this->_bodyCanonSpace = false;
}
/**
* Writes $bytes to the end of the stream.
*
* Writing may not happen immediately if the stream chooses to buffer. If
* you want to write these bytes with immediate effect, call {@link commit()}
* after calling write().
*
* This method returns the sequence ID of the write (i.e. 1 for first, 2 for
* second, etc etc).
*
* @param string $bytes
*
* @throws Swift_IoException
*
* @return int
*/
// TODO fix return
public function write($bytes)
{
$this->_canonicalizeBody($bytes);
foreach ($this->_bound as $is) {
$is->write($bytes);
}
}
/**
* For any bytes that are currently buffered inside the stream, force them
* off the buffer.
*/
public function commit()
{
// Nothing to do
return;
}
/**
* Attach $is to this stream.
* The stream acts as an observer, receiving all data that is written.
* All {@link write()} and {@link flushBuffers()} operations will be mirrored.
*
* @param Swift_InputByteStream $is
*/
public function bind(Swift_InputByteStream $is)
{
// Don't have to mirror anything
$this->_bound[] = $is;
return;
}
/**
* Remove an already bound stream.
* If $is is not bound, no errors will be raised.
* If the stream currently has any buffered data it will be written to $is
* before unbinding occurs.
*
* @param Swift_InputByteStream $is
*/
public function unbind(Swift_InputByteStream $is)
{
// Don't have to mirror anything
foreach ($this->_bound as $k => $stream) {
if ($stream === $is) {
unset($this->_bound[$k]);
return;
}
}
}
/**
* Flush the contents of the stream (empty it) and set the internal pointer
* to the beginning.
*
* @throws Swift_IoException
*/
public function flushBuffers()
{
$this->reset();
}
/**
* Set hash_algorithm, must be one of rsa-sha256 | rsa-sha1.
*
* @param string $hash 'rsa-sha1' or 'rsa-sha256'
*
* @throws Swift_SwiftException
*
* @return $this
*/
public function setHashAlgorithm($hash)
{
switch ($hash) {
case 'rsa-sha1':
$this->_hashAlgorithm = 'rsa-sha1';
break;
case 'rsa-sha256':
$this->_hashAlgorithm = 'rsa-sha256';
if (!defined('OPENSSL_ALGO_SHA256')) {
throw new Swift_SwiftException('Unable to set sha256 as it is not supported by OpenSSL.');
}
break;
default:
throw new Swift_SwiftException('Unable to set the hash algorithm, must be one of rsa-sha1 or rsa-sha256 (%s given).', $hash);
}
return $this;
}
/**
* Set the body canonicalization algorithm.
*
* @param string $canon
*
* @return $this
*/
public function setBodyCanon($canon)
{
if ($canon == 'relaxed') {
$this->_bodyCanon = 'relaxed';
} else {
$this->_bodyCanon = 'simple';
}
return $this;
}
/**
* Set the header canonicalization algorithm.
*
* @param string $canon
*
* @return $this
*/
public function setHeaderCanon($canon)
{
if ($canon == 'relaxed') {
$this->_headerCanon = 'relaxed';
} else {
$this->_headerCanon = 'simple';
}
return $this;
}
/**
* Set the signer identity.
*
* @param string $identity
*
* @return $this
*/
public function setSignerIdentity($identity)
{
$this->_signerIdentity = $identity;
return $this;
}
/**
* Set the length of the body to sign.
*
* @param mixed $len (bool or int)
*
* @return $this
*/
public function setBodySignedLen($len)
{
if ($len === true) {
$this->_showLen = true;
$this->_maxLen = PHP_INT_MAX;
} elseif ($len === false) {
$this->_showLen = false;
$this->_maxLen = PHP_INT_MAX;
} else {
$this->_showLen = true;
$this->_maxLen = (int) $len;
}
return $this;
}
/**
* Set the signature timestamp.
*
* @param int $time A timestamp
*
* @return $this
*/
public function setSignatureTimestamp($time)
{
$this->_signatureTimestamp = $time;
return $this;
}
/**
* Set the signature expiration timestamp.
*
* @param int $time A timestamp
*
* @return $this
*/
public function setSignatureExpiration($time)
{
$this->_signatureExpiration = $time;
return $this;
}
/**
* Enable / disable the DebugHeaders.
*
* @param bool $debug
*
* @return Swift_Signers_DKIMSigner
*/
public function setDebugHeaders($debug)
{
$this->_debugHeaders = (bool) $debug;
return $this;
}
/**
* Start Body.
*/
public function startBody()
{
// Init
switch ($this->_hashAlgorithm) {
case 'rsa-sha256':
$this->_bodyHashHandler = hash_init('sha256');
break;
case 'rsa-sha1':
$this->_bodyHashHandler = hash_init('sha1');
break;
}
$this->_bodyCanonLine = '';
}
/**
* End Body.
*/
public function endBody()
{
$this->_endOfBody();
}
/**
* Returns the list of Headers Tampered by this plugin.
*
* @return array
*/
public function getAlteredHeaders()
{
if ($this->_debugHeaders) {
return array('DKIM-Signature', 'X-DebugHash');
} else {
return array('DKIM-Signature');
}
}
/**
* Adds an ignored Header.
*
* @param string $header_name
*
* @return Swift_Signers_DKIMSigner
*/
public function ignoreHeader($header_name)
{
$this->_ignoredHeaders[strtolower($header_name)] = true;
return $this;
}
/**
* Set the headers to sign.
*
* @param Swift_Mime_HeaderSet $headers
*
* @return Swift_Signers_DKIMSigner
*/
public function setHeaders(Swift_Mime_HeaderSet $headers)
{
$this->_headerCanonData = '';
// Loop through Headers
$listHeaders = $headers->listAll();
foreach ($listHeaders as $hName) {
// Check if we need to ignore Header
if (!isset($this->_ignoredHeaders[strtolower($hName)])) {
if ($headers->has($hName)) {
$tmp = $headers->getAll($hName);
foreach ($tmp as $header) {
if ($header->getFieldBody() != '') {
$this->_addHeader($header->toString());
$this->_signedHeaders[] = $header->getFieldName();
}
}
}
}
}
return $this;
}
/**
* Add the signature to the given Headers.
*
* @param Swift_Mime_HeaderSet $headers
*
* @return Swift_Signers_DKIMSigner
*/
public function addSignature(Swift_Mime_HeaderSet $headers)
{
// Prepare the DKIM-Signature
$params = array('v' => '1', 'a' => $this->_hashAlgorithm, 'bh' => base64_encode($this->_bodyHash), 'd' => $this->_domainName, 'h' => implode(': ', $this->_signedHeaders), 'i' => $this->_signerIdentity, 's' => $this->_selector);
if ($this->_bodyCanon != 'simple') {
$params['c'] = $this->_headerCanon.'/'.$this->_bodyCanon;
} elseif ($this->_headerCanon != 'simple') {
$params['c'] = $this->_headerCanon;
}
if ($this->_showLen) {
$params['l'] = $this->_bodyLen;
}
if ($this->_signatureTimestamp === true) {
$params['t'] = time();
if ($this->_signatureExpiration !== false) {
$params['x'] = $params['t'] + $this->_signatureExpiration;
}
} else {
if ($this->_signatureTimestamp !== false) {
$params['t'] = $this->_signatureTimestamp;
}
if ($this->_signatureExpiration !== false) {
$params['x'] = $this->_signatureExpiration;
}
}
if ($this->_debugHeaders) {
$params['z'] = implode('|', $this->_debugHeadersData);
}
$string = '';
foreach ($params as $k => $v) {
$string .= $k.'='.$v.'; ';
}
$string = trim($string);
$headers->addTextHeader('DKIM-Signature', $string);
// Add the last DKIM-Signature
$tmp = $headers->getAll('DKIM-Signature');
$this->_dkimHeader = end($tmp);
$this->_addHeader(trim($this->_dkimHeader->toString())."\r\n b=", true);
$this->_endOfHeaders();
if ($this->_debugHeaders) {
$headers->addTextHeader('X-DebugHash', base64_encode($this->_headerHash));
}
$this->_dkimHeader->setValue($string.' b='.trim(chunk_split(base64_encode($this->_getEncryptedHash()), 73, ' ')));
return $this;
}
/* Private helpers */
protected function _addHeader($header, $is_sig = false)
{
switch ($this->_headerCanon) {
case 'relaxed':
// Prepare Header and cascade
$exploded = explode(':', $header, 2);
$name = strtolower(trim($exploded[0]));
$value = str_replace("\r\n", '', $exploded[1]);
$value = preg_replace("/[ \t][ \t]+/", ' ', $value);
$header = $name.':'.trim($value).($is_sig ? '' : "\r\n");
case 'simple':
// Nothing to do
}
$this->_addToHeaderHash($header);
}
/**
* @deprecated This method is currently useless in this class but it must be
* kept for BC reasons due to its "protected" scope. This method
* might be overridden by custom client code.
*/
protected function _endOfHeaders()
{
}
protected function _canonicalizeBody($string)
{
$len = strlen($string);
$canon = '';
$method = ($this->_bodyCanon == 'relaxed');
for ($i = 0; $i < $len; ++$i) {
if ($this->_bodyCanonIgnoreStart > 0) {
--$this->_bodyCanonIgnoreStart;
continue;
}
switch ($string[$i]) {
case "\r":
$this->_bodyCanonLastChar = "\r";
break;
case "\n":
if ($this->_bodyCanonLastChar == "\r") {
if ($method) {
$this->_bodyCanonSpace = false;
}
if ($this->_bodyCanonLine == '') {
++$this->_bodyCanonEmptyCounter;
} else {
$this->_bodyCanonLine = '';
$canon .= "\r\n";
}
} else {
// Wooops Error
// todo handle it but should never happen
}
break;
case ' ':
case "\t":
if ($method) {
$this->_bodyCanonSpace = true;
break;
}
default:
if ($this->_bodyCanonEmptyCounter > 0) {
$canon .= str_repeat("\r\n", $this->_bodyCanonEmptyCounter);
$this->_bodyCanonEmptyCounter = 0;
}
if ($this->_bodyCanonSpace) {
$this->_bodyCanonLine .= ' ';
$canon .= ' ';
$this->_bodyCanonSpace = false;
}
$this->_bodyCanonLine .= $string[$i];
$canon .= $string[$i];
}
}
$this->_addToBodyHash($canon);
}
protected function _endOfBody()
{
// Add trailing Line return if last line is non empty
if (strlen($this->_bodyCanonLine) > 0) {
$this->_addToBodyHash("\r\n");
}
$this->_bodyHash = hash_final($this->_bodyHashHandler, true);
}
private function _addToBodyHash($string)
{
$len = strlen($string);
if ($len > ($new_len = ($this->_maxLen - $this->_bodyLen))) {
$string = substr($string, 0, $new_len);
$len = $new_len;
}
hash_update($this->_bodyHashHandler, $string);
$this->_bodyLen += $len;
}
private function _addToHeaderHash($header)
{
if ($this->_debugHeaders) {
$this->_debugHeadersData[] = trim($header);
}
$this->_headerCanonData .= $header;
}
/**
* @throws Swift_SwiftException
*
* @return string
*/
private function _getEncryptedHash()
{
$signature = '';
switch ($this->_hashAlgorithm) {
case 'rsa-sha1':
$algorithm = OPENSSL_ALGO_SHA1;
break;
case 'rsa-sha256':
$algorithm = OPENSSL_ALGO_SHA256;
break;
}
$pkeyId = openssl_get_privatekey($this->_privateKey);
if (!$pkeyId) {
throw new Swift_SwiftException('Unable to load DKIM Private Key ['.openssl_error_string().']');
}
if (openssl_sign($this->_headerCanonData, $signature, $pkeyId, $algorithm)) {
return $signature;
}
throw new Swift_SwiftException('Unable to sign DKIM Hash ['.openssl_error_string().']');
}
}